Official Go implementation of the Ethereum protocol
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go-ethereum/vendor/github.com/prometheus/tsdb/fileutil/mmap.go

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1.3 KiB

// Copyright 2018 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package fileutil
import (
"os"
"github.com/pkg/errors"
)
type MmapFile struct {
f *os.File
b []byte
}
func OpenMmapFile(path string) (*MmapFile, error) {
f, err := os.Open(path)
if err != nil {
return nil, errors.Wrap(err, "try lock file")
}
info, err := f.Stat()
if err != nil {
return nil, errors.Wrap(err, "stat")
}
b, err := mmap(f, int(info.Size()))
if err != nil {
return nil, errors.Wrap(err, "mmap")
}
return &MmapFile{f: f, b: b}, nil
}
func (f *MmapFile) Close() error {
err0 := munmap(f.b)
err1 := f.f.Close()
if err0 != nil {
return err0
}
return err1
}
func (f *MmapFile) File() *os.File {
return f.f
}
func (f *MmapFile) Bytes() []byte {
return f.b
}